I also found free slate apps and "strobox" which allows you to diagram lighting setups. A sketching app, the Celtx (currently on sale?) Scripts and Shots... Tons of stuff out there for free in the way of iApps
Light meter (icon looks like a regular digital light meter -- turn on the extra info... shows footcandles and lux!) and lux meter (although I may just use the other one now that I found the extra info thingy!)